Hydraulic control apparatus for machine tools



:JMWLL-SJ 194.5-4 R. A. scHAEER ET Al. 2,377,720

HYDRAULIC .CONTROL APPARATUS FOR MACILINE TQOLS Filed June 8, 1940 V 12 Sheets-Sheef June 5', 1945:,- R. A. scHAFER E1- AL VHYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed June 8, `194() 12 Sheets-Sheet 2 June 5, 1945.- R. A. scHAr-'E' ET Al. 2,377,720

HYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed J une 8, 1940 Y 12 Sheets-Sheet 3 gif/ June 5, 1945. R. A; SCHAFER :TAL 2,377,720

HYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed June 8, 1940 12 sheets-sheet 4 GZfezzZrzZ, 4

j-egw, @y ma June 5, 1945. R. A. SCHAFER ET AL 2,377,720

HYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed June 8, 1940 12. sheets-sheet '5 Coarse f/e ed' I 561 a3 SIZ 73.1 1550*Z 9355 619g.; 1z0

June 5. 1945-` R. A. scHAr-'ER ET AL 2,377,720

HYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed June f8. 1940 12 Sheets-Sheet 6 1.5. f ffv'ofyefse Tfddefse 2555' 72 K 5' w, 256 2M, Y

frovezaf A Jung 5, 1945i.

R. A. scHAEl-:R ET AL HYDRAULIC CONTROL APARATUS FOR MACHINE TOLS -F'iled June 8. 1940 Y 12 Sheets-Sheet 7 June`5',194r5.` R. A. scHAr-'ERET AL A 7 2,377,720

HYDRAULIC CONTROL APPARATUS FOR MACHINE TOOLS Filed June 8, 1940 l2 Sheets-Sheet 8 5,4945". A RfA-scHAFR ETAL 2,377,720 A BYDRAULIG 'CONTROL APPARATUS` FOR MACHINE 'rooLs 12 Sheets-Sheet HIIIIIII v. Filed Jane 8. 1940 @S lm, 1 l

UWM.

25g MV R. A. scHAFER ET Al.

' HYDRAULIC CONTROL APPARATUS FOR MACHINE FiledJune 8. 1940 TOOLS 12 sheets-sheet 1o l lim" M11-2: 11ii: :TELE

m-.f---f--Me---U- June 5, 1945. l R. A. scHAr-'ER ET AL 2,377,720 HYDRAULIC CONTROL APPARTUS FOR MACHINE TOOLS I Filed June 8, 1940 12 Sheets-Sheet 11 June-5! 1945.- R.--A CHAFER ETAL 2,377,720

HYDRAULG CONTROL APPARATUS FR MACHINE TOOLS Patented June 5, 1945 HYDRAULIC CONTRL APPARATUS FOR- MACHINE TOOLS i Robert A. Schafer ano Ralph Rom, Richmond, Ind., assignors to The National Automatic Tool Company, a corporation of Indiana Application June 8, 1940, Serial No. 339,476

(Cl. (S-52) 7 Claims.

, trol apparatus of our invention are applicable to ,a large variety of machine tools, for controlling the actuation of the tools toward and :from the work, or conversely, controlling the movement of the work toward and away from the tools, or may be applied to control the movement of any other part of such machine tool. In this application, our invention is, however, described as applied to the control of a horizontal unitary machine tool for performing drilling, tapping, reaming, vfacing, and similar operations.

In machine tools of this general type, as customarily made in the past, the tools were advanced'toward the work and retracted therefrom by a hydraulic piston and cylinder actuatorin which movement wascaused by supplying oil under pressure to one end of the cylinder and permitting it to flow freely from the other end of the cylinder into a drain or sump. 'I'his type of actuator has a, number of disadvantages as compared with our present invention, in that the machinetools, especially if performing a milling operation, tended to grab and draw the head bearing the tool toward the work at a faster rate than that determined by the rate of oil supplied to the cylinder.,

In accordance with our invention, the rate of feed of the tools toward the work is determined by metering devices which control the rate at which the oil may iiow from the end of the cylinder (opposite the end to which the oil under pressure is supplied) to the oil reservoir vor sump. By virtue of this arrangement, the possibility oi the tool pulling into the work dueto the torque pull at the cut is substantially eliminated since such pulling force is resisted by the restricted ilow of oil from the non-pressure end of the cylinder to the sump. A

It is thus an object of our invention to provide an improved hydraulic feeding apparatus for machine tools, whereby the disadvantageous effect of having the machine tool pull is substantially eliminated.

A further object is to provide a hydraulic coninto the work the head became temporarily stopped or slowed down due to increased friction on its slides and to'move at an accelerated rate when the friction had been overcome and a, place of lesser friction encountered. This irregular and sometimes `ierky movement of the head could cause irregularities in the character of themachining operations performed, and was otherwise unsatisfacitory because of the shock, noise, and excessive wear produced as a result of such jerky or irregular movement of the head.

In our invention, this possibility Aof irregular movement of the head is substantially completely eliminated by metering the rate at which the oil ilows from the cylinder to the, sump, rather than by metering the rate at which the oil under prese sure .iiows into the cylinder.

The apparatus Yprovides a hydraulically locked circuit, since one side of the piston isunder full pump pressure, Whereas, the other side of the piston is subjected to the back pressure due to the restricted flow rate of the oil therefrom to 1 the sump. Y

trol apparatus for machine tools in which a part because of the possibility of their eventual failurev ily ilt into the design of the apparatus, and which trol apparatus for machine tools in which the of the machine tool is hydraulically actuated under the control of a directional valve which in turn may becontrolled either by a hand operated pilot valve or :by an automatically operated 'pilot valve, the pilot valves beingof small dimensions and being capable of actuation by the applica tion of small forces, thuseliminating the necessity of providing large powerful Ysolenoids for the actuation of the control valve, and also eliminatingthe necessity for the use of springs. As is well understood in the art, springs in continuous use in apparatus oi' this character are undesirable due to the fatigue factor. By providing easily operable pilot valves, small solenoids which readare comparatively inexpensive may be utilized, and the hazard of using springs avoided.

A further object is to provide a hydraulic control apparatus-for machine tools having a. man- .ually operable pilot valve for controlling the acthe movement of the head to be irregular because erated pilot control valve when the automatic pilot valve is effective, positions the `automatic pilot valve properly with respect to the position of the machine tool part in its cycle, so that the hand pilot valve may :be rendered ineffective at Many time during the cycle, whereupon the automatic pilot valve will be in proper position to control the actuation of the machine tool part through ,its proper cycle of operation.

A further object is to provide an improved hydraulic control apparatus for machine tools in which both automatic and manual control are possible, the manual control being particularly useful when the machine is being set up or tools are being changed, and in which means are provided for rendering the manual control inoperable whenever the automatic control is rendered effectively operable.

A further object is to provide an improved hydraulic control apparatus for machine tools in which both manual and automatic controls are p ovided, and in which means are provided to prevent rendering the automatic control operative unless the hand control is in neutral or stop position, so that the machine may be stopped at any =time in its automatic cycle by shifting from automatic to hand control, and

upon reverting to automatic control the machine may resume operation at the point in the cycle at which the hand operation was interrupted. since, during the time that the machine is being operated under hand control, the automatic A further object is to provide an improved form of hydraulic pilot valve controlled apparatus.

A further object is to provide an improved hydraulic control apparatus for machine tools which is very compact in construction, composed of a few moving parts, which is easily adjusted and regulated, and which may be inexcontrol is actuated (although ineffectively) so of oil to the actuating piston and cylinder of the may be very small andA easily operated and will y be eiectiveJ through a series of valves, to control the application of large hydraulic forces for the movement of parts of the machine tool.

A further object is to provide an improved hydraulic control apparatus for machine tools utilizing two' sources of fluid pressure, one being a high pressure. low volume source and the other being a low pressurehigh volume source,

and applying the hydraulic pressure from saicl`` sources to the hydraulically operatedparts of the machine tool in a manner such that the high pressure low volume source will be used for feeding operations, while both low pressure high volume source and the high pressure low volume source will be used to operate the machine tool upon rapid forward and rapid reverse traverse operations when the resistance to movement of the machine tool part is low, and the speed of movement of such part should be high.

0 A further object is to provide an improved part of the machine tool to be moved) move sequentially to positions which would cause the head .of the machine tool to .,operate through the following cycle: From yneutral position through rapid forward traverse, coarse feed, fine feed. stop. and reverse traverse. In this type of control, it was necessary, to initiates, new cycle, to move the "directional control valve past the reverse position. I'his passing over of the reverse position caused a momentary reverse movement of the tool carrying head. which sometimes resulted in an abrupt .iar of the head, with conseuuent noise and wear upon the parts.

In the construction of the present invention.

the directional valve moves fromneutral orl sary for the directional control Yvalve to move through the reverse traverse positionV in order to reach the forward traverse position.

l eration, and may be economically produced.

Further objects will appear fromA the following description, reference being had to the accompanying drawings, in which:

Figure 1 is a side elevational view of an ex', emplary machine tool embodying the Ahydraulic control of our invention; I

Figure 2 is an elevational view of the hydraulic valve being shown in position forcontrol by the automatic pilot valve; i

Figure 8 is a view similar to Figure '7 with the throw-over valve in position for control by the manually operated pilot valve;

Figures 9, 10, l1, i2, and 13 are vertical sectional views showing the directional valve, re-

spectively, in the stop or neutral position. in

the rapid forward'trazveise position, in the coarse g feed position, in the ne feed position, and in the rapid reverse traverse position;

Figure 14 is a developed sectional view taken` on the line 14-14 of Figure 13;

Figure 15 is a developed sectional view taken substantially on. the line l5-I5 of Figure 1;

Figure 16 is Va. sectional view of the pressure maintaining valve;

Figure '17 is a sectional-view through the low the'main control or directional valve;

Figure 18 is a full size sectional view through the high pressure relief valve? Figures 19 and 20 are transverse sectional views of the high pressure relief valve taken on the lines I9-I9 and 2li-20 of Figure 18;

Figuren is e fun size sectional view through the longitudinal center of the low pressure relief valve;

Figure l22 is a-fragmentary transverse sectional view of the hydraulic motor for `operating lthe automatic pilot valve, the "parts thereof being shown in neutral position;

Figures 23 and 24 areviews similar to Figure 22 showing the parts in the positionA assumed and t1. which are adjustably secured upon a support 48, which is rigidly secured to th sub-base 25. The top cam surfaces of the dogs 45, d8, and 41 are at unequal elevations so that as the hous ing moves with respect to the sub-base 2G, the lever 44 will be pivoted through an angle determined by the height of the tops of the dogs 45,

l pressure check valve showing `its connection with 43, and 41.

The. left-hand arm of the lever 4t is operatively connected with an arm by a rod 52, the arm 50V being connectedto the automatic pilot valve, as-wlll hereinafter be described, in detail.

A manually operable handle 54 is connected to the hand Pilot valve, and a handle 55 is connected to a throw-.over valve and locking mechanismfby which the automatic pilot valve and thehand vpilot valve may -be alternatively rendered ineilective, and by the operation of which the hand pilot valve vmay be locked in position when the automatic pilot'valve is rendered eiective'to control the operation of the machine.-

during rapid forward traverse andduring rapid f reverse traverse respectively.

. vFigures 25 and v25A are end elevational and side elevational views of the vane of motor shown in Figures 3, 22, 23, and 24;

Figure 26 is a diagrammatic view showing the complete system and circuits for the operation of the solenoids; and,

i Figure 2-'1 is a simplied diagram of the complete hydraulic system showing in a general way the operating.- relationship between the various parts of thesystem.

General description "In order that the necessarily rather compli-A the hydraulic v A panel 58 is secured tothe work piece base 36 and carries four push buttons 59, 60, 6|, and 52, whichv operate electric switches. ton 59 operates to closel a switch 59a (Fig. 26)

which re-sets the hydraulic control 'unit to initiate acycle of .the tool head, while the push button closes a switclr 55a (Fig. 26) to close and thereby to initiate `a rapid reverse traverse. operation of the machine tool head.\ Push button el starts che electric motor n, wnucpush button 52 stops this motor by the use of-a suitable switch mechanism. l 'Y Upon the opposite side of limit switch 84 which is secured tothe housing and has a switch actuator 58 which is engageabie with a dog il adjustably positioned upon a rail 'I0 securedo the sub-base 25. The limit switch cated and detailed description of the invention may be more readily followed, it is preceded by fthis brief general description or the machine tool and the hydraulic control apparatus therefor.

Referring particularly to Figs. l, 2,V and 26, our

invention is illustrated as applied to an automatic drilling machine comprising a self-oon'-A tained unit consisting of .a housing 25 which is mounted to slide on a stationary sub-base 26. The housing is hollow so as to forma reservoir or sump S and includesa tool carrying head 21, a high pressure low volume pump' 12, and a low pressure4 high volume pump 43, theinlets of which are suitably', connected to a strainer 38 located near the bottom of the sump S.4v The pumps 12 and 43 as well as the tools 3l are driven by an electric motor 2B.

A hydraulic feed cylinder 29 is rigiaiy secured to the housing 25 and has a piston 3l carried'by a piston rod 32 which is rigidly secured to a portion of the sub-base ,26. 4'I'he sub-base 26 is suitably secured to the machine base 34. which may be formed integrally with or may be secured to a 4 wo'rl; supporting basel 35 having a table 35 formed integrally with or secured thereto.' A piece of work 4l upon which the drills 3| are to operate is illustrated as being bolted t'o the tablefll. The control unit 95 is mounted upon the side of the housing 25, covering an opening formed in the latter, and comprises a lever 44 which is suitably mpivoted on a downwardly projecting portion of the housing 25 and the right-hand arm of which is` adapted to contact seriatim with dogs 4 5, 45,

84 includes a contact'arm 84a (Fig.`.26)', which,

switch 50a. i,

Referring. now to the diagrammatic view of Figs. 26 and 27, it will be notedthat the low presit will be' noted. is connected in parallel with the 'sure pump 42 draws'the operating fluid,which will -hereinafter'be referred to as'oil, from "the sump S and delivers it under pressure to a pressure maintaining valve body 54 having -a .spring-pressed valve 14 which may be designed to open at a pressure in the order of 50 pounds Ivper square inch. A conduit 90 is' connected to 'the valve body I4 so as to be'supplied with oil l at the pressure at which it is maintained 'in the T.

4 14 is ell'ective to maintain a pressure diierential.

- (of approximately iifty pounds per square inch) tional valves.

'Ihe chamber 5I behind the check valve '14 is connected by a conduit SLI to a valve chamber 91.2. Generally.' speaking, the oil supplied through the conduit am is provided for the ccf tuation of thecylinder and piston 29, 3F duri rapid forward and rapid traverseoperation` of.

the latte, while the oil supplied through the conduit il isp'rovided for the actuation `of thef pilot and directional valves and the hydraulic motor for operating the pilot valve. The valve between the .pressures in, conduits and SLI, so that suillicent able for the operation A high pressure low volume pump 12iflikewise draws oil -from the sump S and discharges it un- 4 deripressure (ofi approximately -five hundred V.pounds Aper square inch) through a` conduit 13,

which, as will be described hereinafter, is; connected by conduit 12.2 to a high pressure relief valve by which the pressure. in' the conduit is Push blltthe housing 25 is a' pressure will always 'be avail-v lof the pilot and direcstub `shaft 92.

4 l l maintained, and isconneca by a conduit 1u through the directional valve to supply oilfor operating the cylinder and piston 2,9, I during f coarse feed and nne feed portions of the operating cycle.. 1

In the foregoing paragraph, and in the following 'de iled description of the invention, in order to f cilitate following the hydraulic circuits,

all passageways, conduits, ports,I and the like,

similarly, au passageways, etc., through which oil is at all times free to discharge to the sump will be followed by the letter S, which should -be interpreted to mean, from which the oil mayv flow freely to the sump.

Hand to automatic throw-over valve As previously stated, the apparatus of\our'in vention may be manually controlled, or may be automatically controlled. There is thus a hand operable pilot valve and an automatically operated pilot valve, the pilot valves'being generally similar and each being capable of controlling the position of the directional valve. The means for determining which of these two pilot valves shall control the operation of the directional valve consists o1" a throw-over valve which is operated by the handle 56. The handle 50 is suitably secured to a stub shaft-92 which is journaled in an end block 94 suitably secured to the main panel 96.

' As shown in Figs. 7 and. 8, the lower'end of the stub shaft 92 has pinion teeth-,98-fornied thereon l for engagement with a rack |00 formed on the throw-over valve |02. 'I'he throw-over valve |02, when in the position in which it is shown in Fig.

. 7, renders the hand pilot valve inoperative, and

when in the position shown in Fig.. 8 renders the 1automatic pilot valve inoperative.

As shown in Fig. .3, the handle 54 is connected to a handpilot valve |03, the. hand pilot valve being surrounded by a follower.s leeye valve and having a portion |01 of increased diameter provided with a .hole |09 to receive a locking pin Hand and automatic pilot valves The conduit en (Fig. 26) has two branches 90.1 and 90.2 which supply oil under pressure to the hand land automatic pilot valve through ducts 90.3 and 90.4, respectively. The automatic pilot valve |04 is secured to the arm 50, a spring pressed detent |24 being engageable in notches formed in a plate |26 so as tohold the arm 50 in the position to which it is moved by the dogs 45, 40, 41.

The handle 54 has a similar datent |20 engageable with recesses formed in the plate |30.

'I'he automatic pilot valve `|04 has a follower sleeve valve |06, .having a pinion ||0 for'med integrally'therewith, the corresponding: hand follower sleeve valve |06 having a similar pinion ||5 formed integrally therewith, the pinions |I0 and ||5 meshing with a pair of racks |52'and |3|v formed on a directional valve |90, which virillbe describfed in further detail hereinafter, the present consideration being that the follower sleeve valves |05 and |06 always move through corresponding angular` distances by .virtue of the fact that each is geared to tle directional valve-III. 'I'he sleeve valve |05 has an annular port 90.5 which, through ports 90.1, communicates with a chamber 90.9 formed by milling away portions of the pilot valve |03. Chambers 90.|| and 90.|0

communicate with the chamber 90.9 through pairs of ducts 90. 5 and 90. 1, respectively, while chambers |355 and |918 are formed in the pilot valve |03 and communicate with a drain duct |098.

In a similar manner, the automatic pilot valve |04 has Aa chamber 90.|0 which communicates withthe drilled passageway 90.4 throughports 90.8, th`e "chamber 90.|0 communicating with chambers 90.| 2 and 90.|4 through pairs of ducts ,90.I6' and 90.|8, respectively. Chambers .|365

and |38S formed in the valve |04 communicate4 with an axially drilled passageway |40Sthrough ports |42S and |44S,respectively, .as shown in Figs. 4 and 6. i

The chamber 90I0I is of the irregular'shape illustrated, so that the hydraulic pressure exerted upon the walls of this chamber will be exactly balanced by-'the hydraulic pressure'exerted upon the walls of chambers 90.I2 and 90.|4.l The pilot valve sleeve |06 has an externalA annular groove |46 which -communicates with'a cross drilled passageway |46.2 whichleads to an annulargroove |46.4 (Figs. I and-8) formed in theported sleeve I2 of the throw-over` valve |02'. From the groove formed at the endof a rack ||3 which is enga'geable with the pinion teeth 99'formed on the A spring pressed detent ||4, en-

gageable with notches formed in the rack H3, is

adapted to hold the rack in either of its extreme positions with the locking pin in engagement withihev hole |09 or free from engagement therewith. By virtue of this constructiom'wlen the throw-over lever 50 is shifted to its upper (Fig.

2) or automatic position, the hand pilot valve f lever ,54 is locked in position.

The throw-over valve |||2 cooperates with a ported sleeve ||2 which is pressed into a bore H6.

in the panel 96 and' has a plurality of ports, here-- inafter to be described in detail, some of which ||8 and |20 formed. in the throw-over valve |02. Thethrow-over valve has an axially drilled hole |22S extending from end to end thereof to permit ilowlof oil whenever this valve is shifted, the

-end of the bore ||6 being in communication wit the sump through a passageway VI 20S.

-may be interconnected by annular passageways |46.4 the oil may flow throughthe annular passageway I9 (when the throw-over valve is in the'automatic position, as shown in Fig. 7.) to an annular groove |48 which, through a duct represented by the dot-dash line |48.' I, communi- 'cateswith the right-hand end (Fig. "1) of directional valve cylinder |52. It will be vnoted from Fig. 8 that oil cannot escape from the passagew'ay |46.2 when the throw-over-valve |v02 is shifted .to the handv control position.

vThe followersleeve |06 of the automatic 'pilot valve hasan Iannulargroove |54 which, as shown in Fig; 6, isin communication with a .cross drilled duct |54.2, the duct |54.2 leading to an vannular passageway |54.4 formed in the throw-over valve sleeve |12, the annulus |54.4 rbeing connected with' asimilar, annular groove |56 and a suit- 'able passageway represented by the dojt-dash line I|i6L| withthe left-hand end of directional valve cylinder |\2. J

In a similar way, the chambers |35S and |318 communicate 'with the axially drilled hole |99S f th\e hand pilot valve |03, and the hand pilot leading to an'annular passageway |45.2' formed in the sleeve ||2 of the throw-over valve |02. An annulus |55 formed in the manualpilot valve sleeve |05 communicatesv with an annu1us,|55.|

in the throw-over valve sleeve ||2 through av cross drill hole |55.2. Thus, when the throwover valve is shifted to the'hand position, as shown in Fig. 8, the annulus |55.| 'communicates through the annular passageway ||6 on thethrow-over valve |02 with the annulus |48, the latter being in communication with the right-hand end of directilonal valve cylinder |52 through the duct |40.

Similarly, when thev throw-over valve is in hand control position, as shown in Fig. 8, the annulus |45 communicates, through cross drilled hole |45.|, annulus |45.2, annular passageway of the throw-over valve, with annulus |56, and hence through conduit |56.| with the left-hand end of the directional valve cylinder |52.

It will be noted from Fig. 4 that the section of the automatic pilot valve |04 between chambers 30.|2 and |368 is a generally diamond shape, to form a slide valve with respect to port |43.|

formedin the valve sleeve |06. ,.Similarly, the

section of the .pilot valve |04 between the chamoff valve for a port |54.| formed in the sleeve |06. The sleeve |05 of the'manual pilot valveY |03 has ports corresponding with the ports |46.| and-|54.I. The automatic pilot valve is adapted to be operated by a hydraulic motor (designated generally by the reference character |53 and shown in detail in Figs, 22 to'25A) controlled by solenoids which in turn are controlled bythe switches 53a, 50a, and 64a, as will be more fully described hereinafter'. s

Disregarding for a moment the functions of thev (d) rapid forward traverse; and (e) rapid reverse traverse. t l

These five positions of the directional valve are shown in Figs. 9, 12,11510, and 13, respectively.

It will be understood |52 flows through the conduit |48.|, throughfthe annulus |48, annular passageway I8 vof the throw-over valve, annulus |45.4 oi the throwa over valve sleeve, cross drilled duct |462, annulus |46 of the pilot valve sleeve |06, port |46.|, and hence to chamber |S. Oil under pressure is thus supplied to the left-hand end of the directional valve |33 and permitted to flow to the sump from the right-hand end thereof. The directional'valve |33 thus moves to the right (Fig. 7)

and by this movement through its rack |32 ro- 1 i tates pinion'l l0 clockwise.

Clockwise movement of the pinion ||0 and consequent clpckwiseemovement of the pilot'sleeve |05 resultsx in closure-of the ports |46.I and |54.|, thereby cutting off the supply of pressure to the left-hand endof the directional valve cylinder |52, and likewise cutting oi the connection to ythe sump .from the right-hand end of the directional` valve cylinder. Thus, any clockwise movement of the pilot valve |04 will immediately re- -sult in vmovement of the directional valve and consequent movement of the pilot valve sleeve 4 |06 in a clockwise direction until the pilot valve Y|04 and sleeve |06 are in the same relative positions as these parts are shown in Figs. 3 to 6 inelusive.

In a similar manner, rotation o'f the pilot valve m vin a counter-cicckwise direction results in a corresponding angular movement of the pilot valve sleeve |06 and leftward displacement of the directional valve |33.

- The hydraulic circuits which cause the latter operation upon munten-clockwise movementof the pilot valve |04 will now be described. Oil un.

der pressure supplied throughthe port 30.8 ows through the chamber- 30.|0 and passageways 90.|6 to cahmber 30.| 2, through the now uncoveredport |46.|, annulus |46, cross-drilled duct |46.2 to annulus |46.4 .of the throw-over valve, annular passageway |||l of the throw-over valve |02, annulus |43, duct I48.| to the right-hand end of the directional valve cylinder |52, thus applying pressure -to the directionalvalve, causing its movement toward the left. The-oil fr m the left-hand end of the cylinder |52 flows out. ardly through the duct |56.|, annulus |56 of the throw'- over valve sleeve, annular passageway |20 formed j in the throw-over valve |02, annulus |54.,4, duct |54.2, annulus |54, into the then uncovered port |54.| and chamber |308. As the result of the leftward movement of the directional valve |733, the pilot valve sleeve |06 will berotated counterclockwise, and thus follow the movement of the Assuming that the directional valve is in its stop or neutral position, and that the automaticpilot valve |04 is moved clockwise (Figs. 2 and '26) by its hydraulic motor |58, the resulting operations of the pilot valve will takel place substantially continuously, but will be described herein as if they took' piace in a series of separate steps. As soon as the pilot' valve |04 starts to move clockwise, the ports. 146.1 and 154.1 in the pilot valve sleeve |06 will be uncovered. As'a result, oil under pressure in the chamber 30.|4 will ilow .through the port |54.|, annulus |54, cross drilled duct |54.2, to the annulus |54.4 of the.throw\over valve sleeve (and assuming that the throw-over valve |02 is in the automatic position of Fig. 7) through the annular passageway |20 of the throw-over valve and henceto the annulus |56 of the throw-over valve sleeve and passageway |56.| to the-left-hand end of the directional valve cylinder |52. At th'e same time, the oil' from the right-hand end of the directional valve cylinder 75 pilotvalve |04 until the ports |46.| and |54.| are again closed by the pilot valve' |04.

From the foregoing, it will be seen that when the pilot valve |04 is moved any angular distance in either direction, such movement is immediately followed by equal angular movement of the pilot vvalve sleeve |06 and proportional movement of the directional valve |33. In this way, by the application of a relatively small torque to the pilot valve |04, relatively large forces may be hydrau- Alica1ly applied to the directional valve |33 for l the shifting of the latter, and the control is such that. the directional valve |33 follows substantially instantaneously, and in very accurate proportionality. the lmovement of the pilot valve.

Ihe hydraulic circuits which are completed when the throw-over valve is in the hand! control position, asillustrated in Fig. 8, will now be described. Itwill lbe noted from Fig, 8 that the throw-over valve |02 cuts olf communication from the ducts |46.2 and |54-.2 which lead to the automene pilot valve. inademen. it puts the duet Y |45.| in communication with the duct |58.| `and puts the duct |55.2 in communication with the duct |48.|. It will be noted that the ducts |45.|

l and |55.2 correspond respectively with the ducts o i A in which it is shown in Fig. 24. When in this |46.2-and |54.2 of the automatic pilot valve. Thus, when the throw-over valve is in the hand position shown in' Fig. 8, the hand-pilot |03 and its lsleeve will operate in the same manner as above described with reference to the pilot valve l0 |04 and its sleeve |06, to control the shifting oi! the directional valve |33. Since the operation of these parts under hand control corresponds exactly Awith their operation under the control of the automatic pilot valve, it is believed that it is lo unnecessary to repeat the details o! 'the hydraulic. circuits by which the shifting of the directional valve is accomplished under the control of the hand pilot valve |03 and its sleeve |05.

Hydraulic pilot valve molar 2 |33 either to its rapid reverse traverse position 25 (shown in Fig. 13) or to its rapid forward-trav-l erse position (shown in Fig. is controlled by solenoids l|68 and |88, which, as shown in Fig. 26, are adapted to be energized upon the closure of |68 may also be e rgized by closure ot the limiti switchc 64a. The plungers of solenoids |88 and |69 are operatively connected to cylindrical slide valves |10 and |1| respectively, these valves being provided with annular grooves |12 and |13 re.- a5 -spectively, and are slidable in bores |14 and |15 respectively formed in a hydraulic motor casting |16. These valves are urged to their retracted position. (upon deenergization of their respective solenoids) by compression coil springs |11. (0

Branches 90.3 and 90.4 i'rom the conduit 80 lead to the valve cylinders |14 and |15 respectively to furnish the operating iluld for the motor.

- The motor is of the oscillatory vane-type and comprises a hollow cylindrical extension |18 of 45 the automatic control valve 04, the lower end of this extension |18being slotted to receive a vane |80, the ends of which project into arcuate chamvbers |82 and |83, which are in communication with vports |82.| and |83.| respectively. As best 50 shown in Figs..25 and a, the vane |80 is Senerally rectangular in cross section, and has a pair of` passageways |84 and |85 extending longi tudinally therethrough. The passageway |84 has ports |84.| and I84.2 in the opposite-faces of the 65 vane, while the passageway |85 has similar but oppositely facing ports |85.| and |85.2 formed therein. Thus, irrespective of the position of the vane |80, the diametrically opposite portions oi.'y

the' chambers |82, |83 are always in communica- 80 tion with each other. As a result, hydraulic 'forces which are exerted upon the ends o! the vane result in applying solely a turning couple,y (or torque) to the automatic pilot valve 04.

The valves |10 and |1| are normally in the positions in which they are shown in Fig. 22, in which case the chambersl |82 land |83 are both atr atn'iospheric pressure due to the connection of f their passageways |82.| and |83.| with ports 70 |86S and |81S through annular grooves |86.|S and |81.|S formed on the valves |10 and |1I respectively. Thus, under these' conditions, the valve |04 is free to rotate in either direction under the control of the dogs 44, 45, 48. and 41.

When thesolenoid |68 is energized, as occurs when the "stop push button 80 is operated orthe limit switch 84a is operated by the dog 66 (when the head reaches the forward limit of its stroke), the slide valve |10 will be moved to the position position, oil under pressure will ilow through the conduit '30.3 around lthe annular groove |12 of the valve |10, throughthe passageway |82.|, into the adjacent end of chamber |82 and to the far end of chamber |83 through the port |84.2, passageway |84, and port I84.|. The far end of chamber |82, through port |85.2, passageway |85, 1

and port |85.| will be connected to the portion of chamber 3 nearest its passageway |83.|, thence around the annular groove |81.|S. Due to this diieren'tial pressure upon the opposite sides of the end portions of the vane |80, it will rotate solenoid |69. Energization of this solenoid will switches a an 59a respectively. The solenoid ,o

move its slide valve |1| to the position in which it is shown in Fig. 23, thereby causing the automatic pilot valve |04 to rotate clockwise tothe i position` in which it is shown in Fig. 23, this i |04 to its extreme clockwise position, shown in Fig. 23, results in moving the directional .control-- valve l33to its right-most position, in which it is shown in Fig. 10, with the result, as previously indicated, that the rapid forward traverse portion oi the cycle is initiated.

Low pressure relief-valve As previously mentioned, the low pressure pump 43 supplies oil under pressure'past the pressure maintaining valve 14 to the' conduit 9|.l and hence .to the chamber 9|.2. The end of this chamber 8|.2 is closed -by arspring-pressed check valve |90 which prevents ow of oil from the mixing chamber 13.2,to the chamber 9|.'2. This 4check valve permits the discharge of. the low pres' sure pump 43 t6 mix with that of the high pressure pump 12 whenever the pressure in the conduit 13 drops appreciably below that in conduit 9|.|, as'will usually occur .during the rapid forward o'r rapid reverse traverse portions of `the operatingcycle. Thus the output of both pumps is utilized during those portions of the cycle which do not require highV pressure `in the cylinder 28. f The chamber 9|.2 is 'in free communication with an annular groove 9|.3 formed in a bore |92 for the low pressure relief valve. As best shown in Figs. 15 and 21, this low pressure relief valve bore |92 has additional anri/ular grooves |93S. |93.|S which are connected .by passageway |93.2S, |93.3S, and |93.4S.

The bore |92 has a.fo`urth annular groove |94 which is connectedby a passageway |94.| and a conduit |941 with a port |'94.3 (Figs. 9 to 13 and 27) formed inthe directionallvalve casting. As will be apparent from Figs. 9 to 13, port I94.3 is closed by a land |91 on the directional valve |33 during the rapidforward traverse and by load on the pump driving motor thev adjacent land |82 during the rapid reverse traverse portions of the cycle. However,V during l the coarse feed and fine feed portions of the cycle (Figs. 11 and 12), this port is in communication withapassageway ISIS.

-A valve member 200 is freely reciprocable in the inner end of the bore |02. its lower end being subjected to pressure through an axial passageway 9|.4 which is connected to the annular groove 8|.2 by a port 2M. Outward movement of the valve member 203 under the pressure thus exerted against its inner end is resisted by a spring 202, the outer end of which abuts against a plug member 204 which is threaded in the outer end of the bore |92. Within the plug 204 is an axial passa'geway 205 which forms a guide for a poppet valve 203 whichis pressed inwardly by a compression coil spring`20l, the degree of compression of which' may be varied by adjustment of a plug 2 |0 threaded in the member 204 and locked in position by a cap nut 2|2. 'Ihe annular chamber 9|.3 is in communication with the interior of the valve 200 through a small throttling port SLB so that oil pressure bis exerted upon the inner end ofthe `poppet valve 203.

\ It will be understood that under normal circumstances, the opposite ends o'f the valve 200 will be subjected to the same pressure due to the communication port |.0 so that the valve 200 is'rea'dily maintained in closed position by the spring 202. However, when the pressure in the .v

annular chamber 0|.2 rises above a predetermined value, the puppet va1ve zoe vwill be moved outwardly against the force of the spring 208v 201 is uncovered. thus permitting rapid escape of the oil from the space above the` until its port valve 200, since the annulus |93.|S is substantially at atmospheric pressure.' The port 201 is considerably larger than the port SLG, and as a result, the pressure on the outer end of the valve 230 will be reduced so that the oil -pressure on Vthe inner end of the valve 200 will move this valve outwardly to open a path of communication be- 1 tween the annular chambers 0|.3 and |938, thus relievingthe pressure on the discharge of the low pressure pump 43, and preventing the latter Y pump from building up an excessive pressure, especially during the rapid forward and reverse traverse portions of the operating cycle.

During the` coarse and fine fed portions Voi the operating cycle, the passageway |94.| is connected to the sump through its conduit I94L2, since, under these circumstances, this passageway is not 4covered by the land |96 of the directional valve |33 (Figs. 11 and 12) and the oil may escape `therefrom to the sump through the passageway |228. When the passageway |94.| lis thus con-l nectedto the sump, the valve 200 will, of course, be unbalanced and move outwardly to bypass the discharge of the "low pressure pump 43 to the ,'acting against the force of sump at a low pressure determined in part bythe l strength of the spring 202, and thus Adecrease the during the feeding portions or the cycle.` Y

High. vpressure relief `'vulve `Means are -provided to prevent the high pres-` qsure pump 12 from building up excessive presmeans comprising a high pressure relief valve. most clearly shown in Figs. 1s, 19, and' 20. Within the panel there is a bore 2|4 having a liner 2li.. The liner 2liV has external annular grooves 13.2 and 2IIS formed thereithe groove 12.3 being in communication with a crossv .13 .l which connects with'the high A chine tool part is moved is determined by con- 'escape of the oil from the Va valve cooperable with ports 2|8.2S. Communi` cation between the duct 13.0 and groove 13.9| is eil'ected through a plurality oi.' ports 13.8 formed in the liner 2 II. Y I

The valve 220 is held in its lowermost position by a compression coil spring 224, the outer end of which aruts against a valve body 226 which is held ag t the end of the liner 2|3 bya sleeve 228 threaded in the outer end of the bore 2|4. A pilot valve 230 is guided for free reciprocation in bores formed in the valve body 226 and relief valve 220, respectively, this pilot valve 230 having an axially drilled passageway 13.2 which, through the bore 13." and port 13.,| I, is subjected to the pressure in the discharge conduit 13 ofthe high pressure pump. A throttling port 13.|2 connects the outer end of thepassageway 13.9 with the space 23| between thevalve 220 and the valve pilot valve 230 has longitudinal` body 220. The grooves or ports 232 formed therein, these grooves being adapted to connect the space 23| with a chamber 2 I8.2S which, through a radial passageway 2|8.3S and an external longi dinal groove 2|0.4Sconnects with the annular groove 2| 8S.

In operation, whenever the pressure of the discharge or the high pressure pump 12 becomes excessively high, the oil in the chamber 13.|0 will force the pilot valve 230 outwardly against the force exerted by its spring 233, the'degree of compression of which may be regulated by an adjusting screw 234 threaded in a plug 235 and covered by a cap nut 233. As the pilot valve is thus moved outwardly, its arcuate ports 232 will connect the space 23| with the chamber -2|8.2S,

in the chamber 23|, the valve 220 will no longer i be balanced, and the oil pressure on its inner end the 'spring 224 will cause the valve 220 to move outwardly rapidly, thus uncovering the ports sump. This bypassing of high pressure pump will continue until the pressure drops suillciently` that the spring force the pilot valve 230 inwardly so-as to'cut oi! communication between the space 23| Vand chamber 2|8.2S via. the arcuate ports 232. Under these circumstances, the oil continuing to iiow through the throttling 'port 13.|2. will, together with the spring 224, return the valve 220 to normal position. as shown in Fig. V18.

Coarse and ne feed controls I As previously stated, the rate atwhich the matrolling the rate of ilnw of oil from the rod end or the actuating cylinder 2l. The flow from this cylinder may be free for -rapid forward traverse, maybe restricted by an Vadjustable coarse feed maintain the 'pressure in 2|3.2S and permittingr passageway 13.5 to'the i the discharge of the- 233 may valve for the coarse feed, or may be greatly restricted by the adjustable tine feed valve.

Thus, the rate at which the head is moved during the forward feeding portions of the cycle is determined by the rate at which oil may escape through. a conduitI 299 which is connected to the rod end of cylinder 29 (Figs. 26 and 27) and leads to a drilled passageway 269.| formed in the control panel 99 (Fig. 14). The drilled passageway 269.I intersects the directional valve cylinder |92 and has a sidewardly directed branch 299.2 which communicates with a-n annulus 299.3 formed in removable plug 294 secured in the panel 99. The

stem 216 has an axially drilled hole 2998 by which the space in the bore 299 above the piston is at all times in free communication with the sump through the aperture 299S formed in the securing plate 212.

Stem 216 has a pair of arcuate slots 299 formed .therein to form passageways for oil around an annular valve seal 292 formed on the sleeve 219, and thus permit flow of oil from the annulus 299.3. ports 269.4 'and chamber 299.9 through the slots 299.1nto a chamber 294 which is the part of the bore 299 between the piston 219 and the upper end of the sleeve 219. It will be understood that the valve stem l219 is normally in the position in which it is shown in Fig. 14, but that, should the pressure within the chamber 294 become built up to a value suiilcient to cause a piston 219 to compress the spring 292, the piston 219 and the stem 219 will move upwardly, thus partially closing the ports .formed by the arcuate slots 299. These parts thus actas a governor to prevent the pressure within the chamber 294 from exceeding a predetermined value, such, for example, as pounds per square inch.

The rate at which oil may escape from the chamber 294 determines the speed at which the 'cylinder 29 will move during the coarse feed and fine f eed portions of the operating cycle. For the purposeyof controlling the rate at which the oil may escape from this chamber 294 for the coarse feed portion of the cycle. an adjustable coarse feed valve 299 is provided. 4This valve is rotatable in a bore 299 and is non-rotatably secured to a control knob 399which has s pointer on its base flange 392 for cooperation with graduations and indicia etched or otherwise marked upon a plate 394 (Fig. 2). The valve 296 is held within its bore by a bushing 399 and hasan arcuate v-shaped groove 399 of gradually tapering depth formed along a portion of its periphery for registration with a passageway 294.| leading to the chamber 294.

The deeper end of the V-shaped 'groove 399 communicates vwith an axially drilled hole 3|9 formed in the valve 299 through a radially drilled port 3|9.|. It will be understoodthat as the valve 299 is rotated, the crosssectional area of that portion of the groove.399 which is adjacent the passageway 294.| may be varied, and since it is mainly that portion of the groove 399 of least cross sectional area which determines the rate at which oil will now from the passageway 294.| to the drilled hole -3|9, the angular position of the valve 299 effectively determinesthe rate at which the oil may escape from the rod end of the cylinder 29-provided the oil may flow freely from the drilled hole 3|9 of the valve |99.

In the coarse feed position of the valve |33, the oil flowing from the drilled hole 3 I 9 may now with a minimum of resistance to the sump through a passageway 3|9.2 which communicates with a duct 3|9.3 and from the latter duct through the directional valve to the sump. as will appear hereinafter.

When the directional valve is in position for struction as the valve 299, although its V-shaped, restriction groove 3|9 may be cut less deep thanv the corresponding groove 396 of the valve 299.

The valve 3|2 has' a control knob 3|9 secured thereto, this valve having a pointer. cooperable with graduations and indicia formed upon a plate 329 which is suitably secured to the panel 99,

(Fig. 2), the valve being held in position by a bushing 322 threaded or otherwise suitably secured in the panel 99. The valve 3|2 has a port 324s communicating with an axially drilled passageway 3258 which is in open communication with, a' passageway 326s leading to the sump. It will' be understood that the sump is located directly insidey of the panel 99 'so that any passageways, such as the passageway 329s, which' extend to the inner surface of the panel 99discharge into the sump.

From the foregoing, it will be seen that when f the'passageway s I 9.3 is blocked by the directional valve, the oil from the rod end of the cylinder 29, after owing through the governor valve 219. must flow successively through the flow restricting valves 299 and 3|2, which constitute, respectively, the adjustable valves for coarse feed and iine feed portions of the operating cycle.

The directional control valve The directional control valve |33, as previously described, is reciprocable in a cylinder |92, the head ends 329 and 339 forming in effect pistons for reciprocation of the valve. The valve has annular passageways 332, 334, and 339 which are adapted to interconnect certainy of the annular grooves formed in the cylinder |92,

Oil under pressure from the conduit 13 is sul plied through a passageway 13.| and chamber 13.2 to an annulus 12.1. The previously described drilled passageway 269A communicates with an annular groove 269.6 formed in the wall of the cylinder |92. Passageways 339s and 349B, communicating respectively with annular grooves 339s and34IS, discharge directly into the sump.

A conduit 342 connected to the forward end of the4 cylinder 29 leads to a drilled passageway 342A which communicates with an annular groove 342.2 formed in the walls of the cylinder |92. The passageway 3 I 9.3 previously described in connection with the operation of the fine feed con- I trol valve communicates with an annular groove f rectional valve is quickly and accurately deter-V directionll 

